1. Field of the Invention:
The present invention relates to mining machines, in general, and to drum cutter-loader mining machines for underground mining, in particular.
2. Description of the Prior Art:
Through German Offenlegungschrift No. DE-OS 26 33 544 there has become known a mining machine having a first support arm member pivotally mounted at one end thereof to an end of the machine body about an axis which runs at right angles to the longitudinal direction of the machine and is parallel to the mine floor. A second support arm member is pivotally mounted to the free end of the first support arm member about an axis which is parallel the pivoting axis of the first support arm member. The second support arm member is mounted on the side of the first support arm member facing the coal face and carries a cutting drum at each of its two ends. The pivot axis of the second support arm member is located at a position intermediate the spaced cutting drums.
German Offenlegungschrift No. DE-OS 32 16 686 has disclosed a coal-cutting machine having a first support arm pivotally mounted at one end thereof to the machine body with the opposite or free end of the support arm carrying a cutting drum. A second support arm is also carried by the opposite end of the first support arm and it too carries a cutting drum at its free end. Each of the two support arms is equipped with a gear train for transmitting to both cutting drums the driving motion of the motor which itself is housed on the inside of the machine body.
German Patentschrift No. DE-PS 27 32 275 discloses a drum coal cutting machine for the mining of low seams which lie next to the longwall conveyor means and for simultaneously cutting away the mine roof with a "front-running" cutting drum in order to provide free passage of the machine along the mine seam. The machine body is situated in the seam and projects into the coalwinning track but is retained by the longwall conveyor means The machine includes two cutting drums carried above the longwall conveyor means by support arms which are pivotally mounted to the machine body. Also secured to each support arm at a point located behind the cutting drum is a flange-mounted driving motor. By this construction, the axis of the driving motor is spaced from the support arm pivoting axis.
In the case of the mining machine disclosed in German Offenlegungschrift No. DE-OS 33 31 920, however, the motor axis also forms the pivoting axis of the support arm of the cutting drum. The driving motor in this device is connected to the support arm but is mounted inside the machine body so as the be rotatable about its own longitudinal axis.
Because of the narrow spaces which must be navigated in mining underground longwall faces, a premium is placed on keeping the length and height dimensions of the cutter-loader to a minimum. At the same time, however, high driving power is required of the motors which drive the cutting drums in such machines. By necessity, such high-powered motors usually are formed with correspondingly large physical dimensions. In order to avoid increasing the dimensions of the machine body to house the high powered motors, the motors are frequently arranged outside the machine body and fastened to the side walls of the support arms of the cutting drums. When fastened to the support arms, the driving motors may either be situated above the longwall conveyor or arranged in the coal seam winning track behind the cutting drums. In the case of a driving motor which is situated above the longwall conveyor means, there are instances, i.e., the lowest drum positions, wherein the maneuverability or height adjustability of the motor leads to a restriction in the cross-section of the machine bridge through which debris carried by the conveyor must pass. Furthermore, the installation of an auxiliary drum at the leading end of the machine is complicated with such a positioning of the cutting drum drive motor.
It is also possible to position the driving motors in the coal seam winning track behind the cutting drums. However, such positioning of the driving motors is feasible only if it can be assured that a free path for each of the driving motors can be cut by the cutting drums in both directions of travel of the machine. Naturally, the range of vertical adjustability of the cutting drums is considerably restricted by this requirement, particularly if the motor diameters and cutting drum diameters do not differ greatly from one another.
An advantage exists, therefore, for a drum cutter-loader having cutting drum drive motors mounted outside of the machine body which neither reduce the pass-through cross-section of the machine bridge nor impair the height adjustability of the cutting drums.
It is therefore an object of the present invention to provide a cutter-loader mining machine having cutting drum drive motors mounted outside the machine body which do not disadvantageously reduce the debris pass-through cross-section of the machine bridge.
It is a further object of the present invention to provide a cutter-loader mining machine having cutting drum drive motors mounted outside the machine body which do not impair the height adjustability of the cutting drums.
Still other objects and advantages will become apparent when one considers the attached drawings and description of the invention presented hereinbelow.